Method and apparatus for indicating track conditions

ABSTRACT

Changes in acceleration caused by local track conditions are directly or indirectly measured as a car moves over a track section. The resultant signals are totalled to produce a signal or parameter characteristic of the track section condition, and this is compared with a comparison signal characteristic of a track condition norm.

United States Patent Schubert 5] Feb. 1, 1972 [54] METHOD AND APPARATUS FOR 3,353,404 11/1967 Swift ..73/l46 INDICATING TRACK CONDITIONS 3,383,913 5/1968 Swift ..73/l46 72 lnvent E on Schube t Vie n A str' 1 or g r n a u la Primary Examiner-Donald O. Woodiel [73] Assignee: Franz Plasser Bahnbaumaschinen, Vienna, Atmmey |(un Kelman Austria [22] Filed: May 8, 1969 [2!] Appl. No.: 822,966

[30] Foreign Application Priority Data [57] ABSTRACT June 25 1968 Austria ..A 6104/68 Changes in acceleratim Caused by rack directly or indirectly measured as a car moves over a track [52 us. Cl ..73/l46 Swim The resultant Signals are totalled to Produce a Signal [51 1 Int. Cl B61k 9/08 or parameter characteristic of the track section condition, and [58] Field of Search ..73/l46; 33/144, 145 this is compared with a comparison signal characteristic of a track condition norm. [56] References Cited UNITED STATES PATENTS 8 Claims, 13 Drawing Figures 2,924,442 2/1960 Gray ..73/492 PATENTEUFEB mm 3,638,482

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E GoN 5w 0 Bear BYW Amrr' METHOD AND APPARATUS FOR INDICATING TRACK CONDITIONS BACKGROUND SUMMARY OF THE INVENTION The present invention relates to improvements in track surveying. I

In US. applications Ser. Nos. 813,854 and 813,855 filed Apr. 7, 1969, entitled Track Surveying Method and Apparatus and Track Surveying, for instance, of which the present inventor is a joint inventor, track-measuring cars are disclosed which continuously measure and record parameters characteristic of the track condition, such as track gage, superelevation, curvature, grade, etc. Such surveys are designed to establish the safety of the track for given train speeds and determine when track maintenance work is required to bring the track back to the desired norm.'

In modern, high-speed track maintenance operations, it is essential to determine the locations where track correction work must be done, and it has been proposed'to use computers to evaluate signals characteristic of given measured track conditions, such as superelevation, grade and alignment. For instance, a norm may be established for each condition, i.e., curvature, superelevation, track gage, grade, these conditions may be continuously measured as a surveying car moves over the track, and deviations from the norm may be measured and fed to a computer which will determine when the track section falls below a given norm by counting the number of deviations in this section. While a variety of surveying methods have been tried, it has not been possible to set up a single characteristic value which generally indicates the entire track condition and is determinative of the safety of the track.

It is accordingly a primary object of the present invention to provide a railway track surveying method and apparatus which uses a single characteristic datum fully reflective of the track condition so that the quality of the track is established by this single parameter or signal.

This and other objects of this invention are accomplished by using as datum the acceleration changes caused by varying local track conditions in the track section being surveyed. The data are related to an assumed uniform speed of a vehicle passing over the track section and they are totalled to produce a parameter or signal characteristic of the track section condition, which signal or parameter is compared with a comparison parameter or signal characteristic of a track condition norm.

It has been found that this single datum related to the acceleration changes actually fully reflects all factors responsible for the quality of the track.

It is preferred to establish data corresponding to the acceleration changes in two mutually perpendicular planes, for instance one defined by the track and the other one perpendicularly extending in the direction of the track. The signals or parameters are separately measured in the two planes, preferably electrically or electronically, and then combined into a characteristic datum, preferably by a vector sum.

The acceleration changes may be measured directly, i.e., by an accelerometer mounted on a car moving over the track at a controllable and measurable speed.

It is also possible, however, to determine the acceleration changes indirectly without using a car with an accelerometer. For instance, changes in a parameter characteristic of successive portions of the track section may be measured, for instance the radii of successive circular arcs which are assumed to form the continuous track section. In this case, the faulty condition of the track section is considered as a succession of curves of the same mathematical function, for instance a series of successive circular arcs. A parameter of these successive curves and the'changes in this parameter are measured, and the corresponding acceleration changes of an imaginary vehicle running over the track section is derived from these measurements and evaluated as though the acceleration changes themselves had been measured.

DETAILED DESCRIPTIONOF DRAWING The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain preferred embodiments of the method and apparatus useful for carrying out the method, taken in conjunction with the accompanying drawing wherein FIG. 1 is a chart aiding in an understanding of the method;

FIG. 2 is a schematic side view of an apparatus useful for carrying out the method;

FIG. 3 is a top view of FIG. 2;

FIG. 4 illustrates the geometry of the measurements carried out by the apparatus of FIGS. 2 and 3; 7

FIG. 5 is a schematic front view of the apparatus of FIG. 2;

FIGS. 6 and 6a illustrate measuring instruments useful in the apparatus of the invention;

FIG. 7 is a diagrammatic illustration of. another useful measuring instrument;

FIGS. 8, 9, 11 and 12 schematically show other embodiments of measuring instruments; and

FIG. 10 is an end view of the instrument of FIG. 9.

DETAILED DESCRIPTION Referring first to FIG. 1, which illustrates the concept of the method of the present invention, the curve in line A of the drawing shows the vertical accelerations measured in a vehicle moving over track sections 1- and [1-11]. The numerals in line B indicate the absolute changes in acceleration indicated by the curve in line A, line C indicating thesum of these absolute acceleration changes in the two track sections. Analogous curves, values and sums for the acceleration in a horizontal plane are given in lines D, E and F. The approximate vector sums of the sums are given in lines G and F (for the accelerations in two mutually perpendicular planes). Line H indicates the actual speeds of the vehicle in the two track sections in kilometers per hour. Line I gives the ratio of the squares of a comparison speed of l00.km./h. and the actual speeds, multiplied by the vector sum of line G.

Totaling the two parameters of line J, the value in line K reflects the sum of the acceleration changes in track section I-III, based on a comparison speed of I00 km./h. If as shown in line L, the experimentally obtained standard or normal parameter for a speed of km./h. is 50 for track section I-III, the track condition given in line M is reflected by the ratio of the actual value 56 to the standard value 50, i.e., 56:50=1.l2 In other words, the track condition in track section I-III deviates from the standard condition by 12 percent and, therefore, requires correction.

In the illustrated example, the vector sums are given only approximately for track sections HI and II-III. If computers are used, exact vector sums may readily be obtained even for very small track sections,,for instance for lengths of a yard or less.

The method of this invention may also be practiced without reference to the speed of the measuring car traveling over the track section whose condition is to be ascertained. If the incorrect position of the track or the individual track rails is considered as a succession of curves of the same mathematical function, for instance as circular arcs, the acceleration f in each arc is determined by the equation f=V-'/13H, wherein V is the vehicle speed and H is the radius of are. In closely adjacent track points I and II, the respective accelerations will be f,=V /l3H, andf =V /l3H The change in the acceleration between two closely adjacent points is equal to the difference of the accelerations:

3 4 ll the ordinate or height of the arc h is measured at the point a curve. In this calculation, it is assumed that the position of of division of a chord having the length a,+b meters ee FIG, the track rails projected into a horizontal and into a vertical 4), h=500ab/H millimeters. plane is a succession of curves of the same mathematical func If it is desired to measure not h but h,, the equation is tion, for instance successive circular arcs.

(1+ b 5 Characteristic values of these arcs or the changes in these hI:h values are measured, for instance changes in the radius of thc arcs, and the accelerations and/or changes in the acceleration or in a horizontal and/or vertical direction are derived therefrom. 500(u+b)b The change in acceleration has been indicated above by the h! 'T following equation:

making 500(a+ If the height of the arc h is measured at the midpoint of a chord which is s meters long,

Thus.

1255 f f V2 (h h h: H

I II I II 6500(a+ Mb and, accordingly, Therefore, as seen in FIG. 4, only the difference between 1 h the ordinates h, and h positioned in space need be measured, 5

H 1255 and the proportional acceleration changes may be readily derived therefrom. The acceleration change f,-f,, is thus derived from the FIG. 2 shows a schematic side view of a surveying apparatus change in the height of the are. with two measuring bogies 4 and 5 which m on a t k 3 The horizontal acceleration changes are obtained in which is curved in a vertical plane, the two bogies being held Changes ofthe horizontal curvature ofthe [rack with at a constant distance by a coupling rod K.

Two axles l and 2 of the measuring bogies 4, Sare posi- (w -w tioned approximately at the height of the point of gravity of 1625s conventional railroad cars. Centrally between the rigidly The acceleration changes for track superelevations are spaced bogies, the two axles of the bogies are spaced by derived as follows: distance v which is proportional to the difference of the An error in the superelevation produces a horizontal moveheights of the arcs of the curved track beneath the bogies. ment of the point of gravity. A sinuous error thus produces a FIG. 3 shows the same surveying apparatus in schematic top sinuous movement of the point of gravity. Centrifugal acvicw, the track shown to be curved also in a horizontal plane. celerations in a horizontal direction of the following mag- Thus, there is also a distance w between the two axles 1 and 2 nitude are exerted upon the point of gravity:

The vertical acceleration changes for the point of gravity are The combined acceleration change is which is proportional to the difference of the heights of the The differences between the heights of the arc are measured arcs in the horizontal plane of the track. in a conventional manner, their vector sums are determined,

In the geometrical projection of FIG. 4, there is shown the and these sums are compared with a comparison norm. geometrical relationship between ordinate h and h,. Points l-E FIG. 6 illustrates an apparatus for inductively measuring the and E are the end points of axles l and 2 at the midpoint of distance. As shown, the end points E, and E of the axles l and the distance between the two measuring bogies. The distance 2 of the two measuring bogies carry respective plates 6 and 6 h,h,, constitutes the vector sum of the parameters w and v. whereon there are mounted windings 7 and 7', respectively, FIG. 5 shows the apparatus of FIGS. 2 and 3 in a schematic which preferably extend radially, as seen in the front view of front view to illustrate this relationship. FIG. 6a. Plate 6 is fixedly mounted on its axle while plate 6' is The horizontal component w and the vertical m o nt v axially movable towards and away from the axially fixed plate. may also be obtained by using a pendulum or a gyroscope, and Plate 6 is universally mounted on ball-and-socket joint 9 and the horizontal and vertical differences of acceleration may be biased against plate 6 by helical spring 8. Both plates are determined by vectors, may be totaled continuously as the surcoated with an insulating film 10 for gliding contact between veying apparatus moves over the track section, and the results the plates. The winding 7 is in circuit with a source 11 of altermay be compared continuously with a standard or norm to 0bnating current. The power lines emanating from winding 7 cut tain an accurate picture of the track condition. across winding 7 and there produce an induction current This condition may also be obtained by reading the results whose potential is measured by voltmeter 12. When the two f a tra k surveying bogie which measures the vertical heights plates are moved in relation to each other, the portions of the of the arc land r, respectively, of the left and right track rail as contacting surfaces are changed correspondingly, thus chang well as the horizontal height of the arc ofthe outer track rail in iflg th induction Current WhiCh, therefore, becomes a sure varying with the relative positions of the end points of the measuring bogie axles.

The plates 6, 6' may also be constituted as condensers, in which case the films 10 form the dielectric. The circuit for such an arrangement is shown in FIG. 7 wherein the plates 6, 6' form the condenser in circuit with a source 13 of alternating current of high frequency. When the two plates are moved in relation to each other, the ammeter 14 will indicate the electrical current corresponding to the varying areas of contact between the two plates.

It is also possible to mount on bogies 4 and 5, as well as on axles l and 2, accelerometers. The difference in the indicated values produces a measure of the track condition dependent on the measuring speed.

FIGS. 8 to 10 illustrate, by way of example, other apparatus mounted on the axle ends of the measuring bogies of determining their position relative to each other.

FIG. 8 illustrates mechanical measuring of the vertical distance between the ends E, and E of the two bogies. Pulleys I6 and [7 are respectively mounted on the ends of the bogies, and a wire or rope I5 is trained over these pulleys and, if desired, an additional guide roller 18, one end of the wire or rope being fixedly anchored to one bogie end, i.e., E while the other end of the wire or rope is attached to spring I9 on the other bogie to keep the wire or rope tensioned. The wire or rope moves a recording stylus 20 which records a curve 22 indicating the vertical distances v on a paper band 21 or like record carrier. A like arrangement for the horizontal produces a record of the horizontal distances w.

FIGS. 9 and 10 are examples wherein the axle ends E, and E carry plates 6a and 6a. The plates carry electrical measuring instruments indicating the varying distances between the axle ends. In the illustrated embodiment, the instruments are windings receiving cores axially moving therethrough, the vertical distances being measured by instrument 23 and the horizontal distances by instrument 24. If the minor error derived from mutual rotation of the plates in respect of each other is neglected, the two instruments produce the components v and w indicating the varying distances of the axle ends.

Since the various electrical measuring instruments are well known, the drawing has not been encumbered with showing the current sources, circuits, amplifiers, etc.

FIG. 11 shows an embodiment wherein the magnitude of the distance between the axle ends E and E is measured. The axle ends have respective brackets 25 and 26 rotatably mounted therein. An electrical measuring instrument 27 is mounted between the two brackets. Furthermore, a mechanical guide 28, which consists of two telescoping tubes, is also mounted between the brackets to protect the electrical measuring instrument 27 from all transverse forces. The mechanical guide is connected to the brackets by universal joints 29, 29 to enable even minor relative movements of the axles to be read by the electrical measuring instrument.

It is desirable to make it possible for an individual in charge of a track maintenance operation to determine the condition of a track section. Therefore, it is quite useful to provide an apparatus for carrying out the invention which may be readily transported. Such an apparatus may include instruments which may be mounted on conventional railway cars or measuring bogies for cooperation so as to produce the desired values. Such instruments may be mounted, for instance, at the ends of railway cars which are coupled together in a train so that the relative position of the car ends may be measured as the train passes over a track section whose condition is to be surveyed.

FIG. 12 illustrates such an arrangement by way of example. The instruments more fully described and illustrated in FIGS. 6 and 6a are mounted on a carrier 32 which may be carried by shoulder straps 30. Setscrews 31 on the carrier are adjusted to mount the instruments properly on the ends of cars 4' and 5'. The carrier housings hold the circuitry and meters which record the readings.

Other modifications and variations will readily occur to those skilled in the art after benefiting from the present teaching without departing from the scope of this invention.

What is claimed is:

1. A method of indicating the condition of a railway track, comprising the steps of moving a car over a plurality of successive sections of the track, the velocity of the car being constant in each track section, producing individual signals corresponding to local changes in acceleration transversely of the direction of elongation of the track, said acceleration changes being due to changing local conditions of the track, totaling the individual signals, the values of the individual acceleration changes being based on a uniform car velocity, to produce an indicium characteristic of the condition of the track consisting of the successive track sections, and comparing the indicium with a like indicium of a track condition norm measured at the same velocity.

2. The method of claim I, wherein said acceleration changes are measured electrically and said signals are electric.

3. The method of claim 1, wherein changes in acceleration are separately measured in two different planes, and said changes are transformed into said measuring signals.

4. The method of claim 3, wherein said planes are perpendicular to each other.

5. The method of claim 4, wherein one of said planes is defined by the track and the other plane extends perpendicularly thereto in the direction of the track.

6. The method of claim 3, wherein the vector sum of all of said indicium is established to arrive at said characteristic nal. 7. The method of claim 1, wherein indicia corresponding to the local positions of the track are measured, and the measured values of the local track positions are transformed into said individual signals corresponding to the local acceleration changes.

8. The method of claim 7, wherein said indicia are the radii of successive curves whose totality constitutes the track positIOII. 

1. A method of indicating the condition of a railway track, comprising the steps of moving a car over a plurality of successive sections of the track, the velocity of the car being constant in each track section, producing individual signals corresponding to local changes in acceleration transversely of the direction of elongation of the track, said acceleration changes being due to changing local conditions of the track, totaling the individual signals, the values of the individual acceleration changes being based on a uniform car velocity, to produce an indicium characteristic of the condition of the track consisting of the successive track sections, and comparing the indicium with a like indicium of a track condition norm measured at the same velocity.
 2. The method of claim 1, wherein said acceleration changes are measured electrically and said signals are electric.
 3. The method of claim 1, wherein changes in acceleration are separately measured in two different planes, and said changes are transformed into said measuring signals.
 4. The method of claim 3, wherein said planes are perpendicular to each other.
 5. The method of claim 4, wherein one of said planes is defined by the track and the other plane extends perpendicularly thereto in the direction of the track.
 6. The method of claim 3, wherein the vector sum of all of said indicium is established to arrive at said characteristic signal.
 7. The method of claim 1, wherein indicia corresponding to the local positions of the track are measured, and the measured values of the local track positions are transformed into said individual signals corresponding tO the local acceleration changes.
 8. The method of claim 7, wherein said indicia are the radii of successive curves whose totality constitutes the track position. 